基于碳点的荧光纳米开关灵敏检测Cu(Ⅱ)离子和焦磷酸盐

利用羟基与氨基在高温条件下反应,不断聚合生成碳点（CDs）,该碳点可发射不依赖激发波长的明亮的红色荧光.将CDs作为目标敏感荧光团时,发现Cu²⁺可特异性猝灭碳点的荧光,而焦磷酸盐（PPi）可在一定程度上恢复上述体系的荧光.其中,Cu²⁺对CDs的荧光猝灭是由于Cu²⁺与CDs发生络合反应,从而发生静态猝灭过程;而加入PPi之后,由于它与CDs的结合能力更强,因此Cu²⁺离开CDs的表面,体系的荧光得以恢复.在此基础上构建了一种高选择性、高灵敏度的off-on荧光纳米开关传感体系,分别用于Cu²⁺和PPi的定量检测,检出限分别达2.14 μmol/L和1.85 μmol/L.该传感体系可应用于实际样品检测,拓宽了荧光CDs的传感应用,为其在生物体内目标分子的检测提供了可能性.     

Titanium Dioxide-Yttrium(III)-Oxide Composite Based Cataluminescence Gas Sensor for Fast Detection of Propylene Oxide

By using nano TiO₂-Y₂O₃ as catalyst, cataluminescence (CTL) phenomenon of propylene oxide (PO) was studied, and it was found that the sensor has high sensitivity and good selectivity for the detection of propylene oxide. The common volatile organic compounds (VOCs) such as acetone, acetaldehyde and benzene show no response to the catalysis of TiO₂-Y₂O₃. Based on this phenomenon, a propylene oxide CTL sensor was designed. The ratio of TiO₂ and Y₂O₃ and the annealed temperatures of the composites were optimized. It was found that when the mass ratio of TiO₂ and Y₂O₃ was 1:3 and the annealed temperature was 500 °C, the catalytic materials showed the best performance. 0.3 L min^?1 of carrier gas flow rate, 490 nm of detection wavelength and 197 °C of working temperature were selected as the optimal working conditions, and under the optimized conditions, the quantitative analysis was performed and CTL intensity was linearly correlated with PO concentration from 4.5 mg L^–1 to 1375 mg L^–1 with a detection limit (3σ) of 1.25 mg L^–1. The sensor was used for quantitative analysis and real-time monitoring of propylene oxide residues in fumigation cereals. The result was consistent with that analyzed by gas chromatography. The CTL sensor proposed here had many merits such as high sensitivity, rapidity and simple operation and had potential application prospects in the rapid detection of propylene oxide in food. At last, the mechanism of catalytic oxidation of PO was discussed as well.     

A sensitive amperometric sensor for hydrazine based on Pt nanoparticles-reduced graphene oxide–multi-walled carbon nanotubes composite

The platinum nanoparticles-reduced graphene oxide-multi-walled carbon nanotubes composite (PtNPs-rGO-MWCNTs) has been synthesised by one-step chemical co-reduction strategy in ethylene glycol (EG) system using sodium citrate as reducing agent. The X-ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), as well as the electrochemical methods have been used for the characterisation of this composite. Benefiting from the large effective surface and good carrier function of rGO-MWCNTs, PtNPs in this nanocomposite have some excellent characteristics such as small particle size, good dispersion, as well as high electrocatalytic activity. Based on this, a new electrochemical sensor for hydrazine has been fabricated using dropping method. Under the optimum conditions, the linear range for the determination of hydrazine by amperometry at 0.20 V (vs. SCE) in phosphate buffer (pH 7.0) is from 2.0 × 10^?7 mol L^?1 to 2.3 × 10^?3 mol L^?1. The detection limit and sensitivity is 4.5 × 10^?8 mol L^?1 (S/N = 3) and 219.7 μA mM^?1, respectively. This sensor has some attractive analytical features such as low detection limit, wide linear range, high sensitivity, as well as good stability.     

Synthesis,characterization, fluorescence imaging,and cytotoxicity studies of a uracil‐based azo derivative and its metal complexes

A uracil‐based heterocyclic azo derivative was prepared by coupling diazotized 5‐aminouracil with 2‐naphthol. This ligand, viz., 1‐(2,4‐dioxopyrimidine‐5‐yl)‐azo‐naphth‐2‐ol (HNAP), was used as a precursor for the synthesis of a series of complexes with manganese(II), cobalt(II), nickel(II), copper(II), and zinc(II) ions. Various physicochemical measurements UV–Visible, Infrared (IR), ¹H NMR, ¹³C Nuclear Magnetic Resonance (NMR), and electron spin resonance (ESR) spectral studies were employed to characterize the ligand and the metal complexes. The ligand showed good selectivity toward Mn²⁺ over the other metal ions with a detection limit of 1.36 μM. This probe was used for the confocal fluorescence imaging of Mn²⁺ ions in Michigan Cancer Foundation‐7 (MCF‐7) cells. The ligand and the metal complexes were tested for their cytotoxicity on the MCF‐7 cell line. It was observed that complexation of HNAP with the metal ions exhibited a promising cytotoxicity.     

DNA-二维纳米片层材料传感平台的构建及其应用

DNA-二维纳米片层材料传感平台结合DNA分子特异性识别能力与二维纳米片层材料优越的物理、化学特性,已成为化学/生物传感器领域重要的研究方向之一.鉴于二维纳米片层材料领域的快速发展,首先介绍了DNA-二维纳米片层材料传感平台的构筑机理,随后重点综述了该传感平台在化学、生物目标物分析检测中的应用研究,并对该类传感平台的应用前景做了展望.     

光致发光与荧光传感 ——光化学基本原理的应用

在物理化学课程教学中融入科学前沿实例可以帮助学生掌握基本原理、提高学习兴趣。光化学是物理化学课程中的重要学习内容,但该部分内容因为涉及到激发态的能量衰减过程而抽象难懂。如果在学习这部分知识时,将该部分原理在指导荧光传感探针设计和研究作用机理方面的应用作为知识灵活运用的实例引入,则对理解和掌握所学内容大有裨益。教学时可通过对荧光传感探针的结构及作用机制、各种光物理过程对荧光发射的影响,以及基于荧光传感原理的科研成果的介绍,使学生体会到物理化学的基本原理在科学前沿中的实际应用。     

基于二维MOFs构建MicroRNA荧光传感器的综合分析化学实验及"赛学结合、三位一体评价"的教学模式设计

本综合性实验将二维金属有机框架(2D MOFs)和MicroRNA (miRNA)分析等前沿研究领域引入化学(材料)本科和研究生实验教学中。主要包括2DMOFs材料的合成及表征、基于2DMOFs的荧光核酸探针构建以及将探针用于miRNA荧光分析等,共10个学时。所需掌握的实验技能包含溶剂热法、离心分散和外标法等基本材料合成和分析化学操作以及荧光、红外、X射线粉末衍射等材料表征和分析方法。我们在实验中实施了一种新型的"赛学结合、三位一体评价"教学模式。在该模式中,学生分组开展团队作业、实验和汇报,不仅要记录实验现象和结果,还需对实验过程录像并总结做成PPT。各组间通过"PPT答辩、实验报告和录像"等进行比赛,三位一体决出成绩。学生在实验中不仅学习了大量实验技能,提高了动手能力,拓展了学术视野;而且通过比赛和教学相结合,激发了你追我赶的学习热情,培养了团队合作精神,调动了学习的主观能动性。该实验和教学模式也适合推广至其他综合化学实验教学中。     

共沉淀法制备的CuGa2O4及其气敏性能

采用共沉淀法制备了CuGa_2O_4粉体,采用X射线衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)等对CuGa_2O_4粉体进行了表征。研究了热处理温度和pH对CuGa_2O_4粉体气敏性能的影响,实验结果表明热处理温度为800℃,pH=6.00(热处理4h)条件下制备出的CuGa_2O_4粉体,在室温下(18±2)℃对三甲胺(TMA)具有较好的气敏选择性和较高灵敏度,对1 000μL·L~(-1)的TMA的灵敏度达到310.1,响应和恢复时间分别约为590和80 s,对1μL·L~(-1)的TMA的灵敏度可达到1.3。     

溶剂热法制备石墨烯/SnO2及其气敏性

采用溶剂热法制备了石墨烯/SnO_2(G/SnO_2)纳米材料,利用扫描电子显微镜(SEM)、X射线衍射(XRD)、拉曼光谱(Raman)等对G/SnO_2进行了表征,研究了石墨烯的量和溶剂热温度对该纳米材料气敏性能的影响。实验结果表明,石墨烯可以调节SnO_2晶体的生长:当石墨烯上清液的量为1 mL、热处理温度为160℃时,制备的G/SnO_2纳米材料在室温下对氨气具有较好的气敏选择性和较高的灵敏度;且当气体体积浓度为1 000μL·L~(-1)时,对NH3的灵敏度为266.4,检出限达到了0.01μL·L~(-1)。     

一个对2,4,6-三硝基苯酚和Fe3+离子具有双重荧光传感行为的层状镉(Ⅱ)-有机配位聚合物

通过水热法合成了一个由三连接的2,3-喹啉二甲酸桥联扭曲的Cd²⁺八面体形成的二维层状配位聚合物[Cd（QDA）]_n（1）。该配合物发射出较强的蓝色荧光并具有很高的热稳定性和化学稳定性。更为重要的是,该配合物在乙醇分散体系中可快速识别痕量的2,4,6-三硝基苯酚和Fe³⁺离子,其对2,4,6-三硝基苯酚的淬灭常数（K_sv）和检测限（LOD）分别为6.61×10⁴ L·mol^-1和0.83 μmol·L^-1,对Fe³⁺离子的淬灭常数和检测限分别为1.74×10⁴ L·mol^-1和2.70 μmol·L^-1。